Siphon



Sept. 13, 1949. A. J. DENIAU SIPHON Filed Oct. 19, 1946 Fig. 1:

Invent 0]: Andre J. Deniau,

8 His Attorney.

Patented Sept. 13, 1949 SIPHON Andr J. Deniau, Paris, France, assignor to General Electric Company, a corporation of New York Application October 19, 1946, Serial No. 704,329 In France October 9, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires October 9, 1963 v 1 Claim. 1 This invention relates to siphons and more particularly to improvements in liquid filled conservator type transformers.

It is a well-known practice to fill transformer tanks and their insulating bushings with dielectric liquid. In order to allow for expansion and contraction of the liquid, it is also common practice to use a so-called conservator or expansion tank which is mounted above the highest liquid filled part of the transformer and which is connected to the transformer tank by means of a suitable conduit. It is necessary to have the lowest liquid level in the conservator above the highest liquid filled part of the transformer so that gravity will keep that part filled. There is usually an air space in the conservator above the highest liquid level therein and this space communicates with the atmosphere through a breather which may be equipped with means for drying the air, if desired.

One of the disadvantages of the above-described arrangement is that if the transformer should spring a leak, which may happen quite easily if one of the insulat n bushings, which normally are made of porcelain, should become cracked, the conservator will empty itself through this leak. As the conservator usually holds about as much liquid as the transformer, it will readily be seen that a transformer containing 40 tons of 011 could lose 2 tons of oil if it should spring a leak, even at the top of the transformer. Not only is the loss of such a large amount of liquid a considerable item of expense but also when the liquid is inflammable, the leakage of such a large amount of liquid represents a serious fire hazard.

In accordance with this invention, there is provided a novel and simple siphon which permits the free interchange of liquid between the transformer and the conservator during normal expansion and contraction of the liquid caused by ordinary temperature changes and which limits the rate of flow beyond which the siphoning action cuts off and further discharge is prevented.

An object of the invention is to provide a new and improved self-limiting siphon.

Another object of the invention is to provide an improved induction apparatus.

A further object of the invention is to provide a new and improved induction apparatus of the liquid filled conservator type.

The invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claim.

In the drawing, Fig. 1 illustrates one embodiment of the invention and Fig. 2 shows a modification thereof.

Referring now to the drawing and more particularly to Fig. 1, there is shown therein the top portion of a transformer tank I which is provided with conventional high voltage bushings 2. Mounted above the tops of the bushings is a conservator tank 3 which communicates with the interior of the tank I through a pipe or other suitable conduit 4 which may be provided with a shut-oil. valve 5, if desired. The conservator tank 3 is always partially filled with a dielectric liquid 6 which is the same as the liquid which completely fills the tank I and which also fills the bushings 2. The level of the liquid 6 in the tank 3 normally varies between an upper limit 1 and a lower limit 8 due to the expansion and contraction of the main body of liquid in the transformer tank I which is caused by both ambient temperature changes and also heat produced by the loading of the transformer in the tank.

A conventional liquid level gauge 9 may be provided on the end of tank 3 and the tank may also be provided with a breather I0 through which air 5 may enter and leave the space in the tank above the liquid level as the latter rises and falls.

In order to permit filling of the conservator and to permit normal interchange of liquid between the tank I and the conservator 3 while preventing loss of liquid in the conservator which would accompany a serious leak in the tank I or bushings 2, a special siphon II is attached to the pipe 4. This consists of a conduit I2 which is connected at its lower end to the pipe 4 and which extends to above the top liquid level in the conservator 3 combined with a second conduit I3 which is connected at its top end by an elbow I4 to the top end of the conduit I2 and whose lower end extends below the bottom level of the liquid in the conservator, combined with a third conduit I5 whose lower end is connected to the lower end of the conduit I3 by an elbow I6 and whose upper open end extends into the space at the top of the conservator above the top liquid level therein. It will, of course, be understood that separate elbows I4 and I6 are not essential and the siphon may consist of a single tube with two right angle bends in place of elbows I4 and I6. The siphon includes a fourth conduit I1 of smaller effective cross sectional area than the other conduits which is connected to an opening in the elbow I 4 and extends down into the liquid below the bottom level thereof.

The operation of Fig. 1 is as follows: When the transformer is filled with liquid in the usual manner, the liquid will be forced up through the pipe 4 after the tank I and bushings 2 have been filled and it will rise in the conduit [2 to the elbow I4. Part of the liquid will then discharge through the smaller cross section conduit ll and the remainder will fill the U tube comprising the parts I3, [5 and I6 and will discharge from the open end of the conduit i5 into the conservator. This primes the siphon.

During contraction of the liquid in the tank I, small conduit H, the elbow l4 and the conduit I2 will act as a conventional siphon and will allow liquid to be withdrawn from the conservator to replace the volume created by the contraction of the main body of liquid. Similarly, during expansion of the liquid in tank l, the liquid will rise in the pipe 4 and will discharge into the conservator in the same manner as when the conservator is being filled except that the how will ordinarily be so slow that all of the liquid will flow into the conservator through the re-- stricted conduit ll.

If now there should occur a leak in the tank or bushings 2, the liquid would ordinarily be siphoned relatively rapidly from the conservator to replace the liquid lost from the parts i or 2 through the leak. By suitably choosing the effective area of the restricted conduit ii, the flow which can occur through this conduit can be made less than would be required to supply the liquid loss through the leak. In other words, the effective area of the conduit ll will be less than the size of the leak.

Under those circumstances, the conduit 4 will draw liquid out of the U tube comprising the parts l3, I5 and 16 until this U tube is emptied at which time air can flow past the elbow l4 and this will immediately break the liquid column and terminate all further siphoning action so that no further liquid will be supplied from the conservator to the transformer.

In the modification shown in Fig. 2, the restricted conduit H has been replaced by a relatively small opening E8 in the elbow i5.

In operation, Fig. 2 is the same as Fig, 1 except that normally siphoning action will take place through the restricted opening 18, the elbow hi and the tube i2. If, however, the rate of flow of fluid out of the conservator 3 through the pipe 4 exceeds that which can pass through 4 tube l5 and up through the tube I3 and past the elbow l4. As soon as this happens, the liquid column or siphon is broken with the result that no further liquid can be siphoned from the conservator 3 through the pipe 4.

It will be seen from Figs. 1 and 2 that the particular point of connection of the restricted passage to the improved siphon is not critical and that it can be connected thereto at various different places while still allowing the automatic cut-ofi operation described above.

While there have been shown and described particular embodiments of the invention, it will be obvious to those skilled in the art that changes can be made. Consequently, it is aimed in the appended claim to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

The combination, with a liquid container whose liquid level is variable between top and bottom levels of a self-limiting siphon for withdrawing liquid from said container, said siphon comprising a conduit extending from below the bottom of said container to above the top liquid level of said container, a second conduit connected at one end to the top of the first conduit and extending down into said liquid below the bottom level thereof, a third conduit connected at its lower end to the lower end of said second conduit and extending above the top liquid level, said third conduit being opened at the top, a quantity of said liquid normally partially filling said second and third conduit. and a fourth conduit of smaller effective cross section than said first conduit connected between an opening in said second conduit and a point in said container below the bottom liquid level therein.

ANDRE J. DENIAU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 7 1,425,843 Dwyer Aug. 15, 1922 1,603,063 Burnham Oct. 12, 1926 1,683,882 Frisk Sept. 11, 1928 FOREIGN PATENTS Number Country Date 377,477 Great Britain July 28, 1932 

